摘要
[目的]采用正交设计优化直链烷基苯磺酸钠(LAS)的超声降解条件,并探讨了其反应机理。[方法]考察了超声频率、超声功率、变幅杆直径和溶液初始pH值对LAS降解效果的影响。对原样及超声降解后的样品进行红外光谱分析和化学分析。[结果]正交设计试验表明,超声降解LAS为一级动力学反应;影响LAS降解的各因素显著性次序为:超声功率>溶液初始pH值>变幅杆直径>超声频率。其中,低频范围内LAS降解率随频率的增加而逐渐降低,在低频条件下超声降解效果最好;大功率超声有利于LAS降解;变幅杆直径对LAS降解率的影响显著。变幅杆直径越大,降解率越高;溶液初始pH值增加,LAS降解率降低,酸性条件有利于LAS降解。红外光谱分析和化学分析结果表明,LAS的超声降解主要得益于空化泡气液界面上和本体溶液内部与空化效应产生的强氧化剂H2O2及具有高度化学活性的.OH进行自由基氧化反应。[结论]该研究得到了LAS超声降解的机理,得出一些有益的结论,为进一步研究工作奠定了基础。
[Objective] The research aimed to optimize the ultrasonic degradation conditions of linear-chain alkyl benzene sulfonate （LAS） by the orthogonal design and discuss its reaction mechanism.[Method] The effects of ultrasonic frequency,ultrasonic power,amplitude transformer diameter,initial pH value of solution on degradation efficiency of LAS were investigated.The infrared spectrum analysis and chemical analysis were made on original samples and degraded samples.[Result] The orthogonal design test showed that the ultrasonic degradation of LAS was a first-order kinetic reaction.The remarkable sequence of these factors that influenced the degradation of LAS was ultrasonic power initial pH value of solution amplitude transformer diameter ultrasonic frequency.The degradation rate of LAS in low-frequency range decreased gradually with the increase of the frequency.Under low-frequency conditions,the effect of ultrasonic degradation was the best.Large-power ultrasonic was helpful for the degradation of LAS.The diameter of amplitude transformer had significant effects on the degradation rate of LAS.The larger the diameter of amplitude transformer was,the higher the degradation rate was.When the initial pH value of solution increased,the degradation rate of LAS decreased.Acid conditions were beneficial to the degradation of LAS.The results of infrared spectrum analysis and chemical analysis showed that the ultrasonic degradation of LAS mainly benefited from the oxidation reaction of free radicals between strong oxidant H2O2 produced by cavitation effect on the gas-liquid interface of cavitated bubble and inside the bulk solution and ·OH with high chemical activity.[Conclusion] The mechanisms and processes of ultrasonic degradation of LAS were obtained and some beneficial conclusions were drawn.The research laid the foundation for further work.
出处
《安徽农业科学》
CAS
北大核心
2010年第22期11933-11935,11956,共4页
Journal of Anhui Agricultural Sciences
关键词
LAS
超声
降解
正交优化
反应机理
LAS
Ultrasonic
Degradation
Orthogonal optimization
Reaction mechanism
